1. Field of the Invention
The present invention relates to the touch-sensing display device and in particular to the touch-sensing display device for reducing the misreporting of the touch point.
2. Description of the Related Art
Given the ubiquity of portable devices such as PDAs and cell phones, touch-sensing display devices have attracted much attention. Generally, a touch-sensing display device is composed of a touch panel and a liquid-crystal module. There are some ways to integrate the touch panel with the liquid-crystal module, such as “out-cell”, “on-cell”, and “in-cell,” as it is known in the art. In short, the techniques can be divided into two types, bonding techniques (also called Lamination) and un-bonding techniques.
FIG. 1A is a schematic diagram illustrating a touch-sensing display device made by a bonding technique. With respect to the bonding technique, because the touch panel 110 and the liquid-crystal module 120 are combined together by the bonding technique, there may exist a gap G1 (as shown in FIG. 1A), such as air, between the touch panel 110 and the liquid-crystal module 120 resulting in poor touch efficiency, such as the touch-sensing display device misreporting a touch point (as described below).
When the user touches the touch-sensing display device, the capacitance value of the capacitor disposed in the touch panel 110 will change. The microprocessor (not shown) compares the variation of the capacitance values (hereinafter is referred to as the differential values) with a threshold so as to detect what point is pressed. In short, the above description is called reporting the touch point, represented by the word “reporting”.
FIG. 1B is a diagram illustrating the touch panel 110 being pressed resulting in a Bending Phenomenon. As show in FIG. 1B, due to the gap G1 between the touch panel 110 and the liquid-crystal module 120, the touch panel 110 bends seriously when the touch panel 110 is pressed heavily. That is to say that the Bending Phenomenon occurs on the touch panel 110. The Bending Phenomenon leads to misreporting of the touch point of the touch-sensing display device, further affecting touch efficiency. It should be noted that when the strength of the press on the touch panel 110 is stronger, the misreporting of the touch point becomes more pronounced.
FIG. 2A is a diagram illustrating the Bending Phenomenon resulting from a heavy press. FIG. 2B is a diagram illustrating the differential values' behavior when touching the touch panel 110 with strong force. Referring to FIGS. 2A and 2B, because a finger or another object presses point A on the touch panel 110 heavily, the whole touch panel 110 bends seriously, further resulting in the differential value of the un-pressed points nearby point A, such as points A1 and A2, varying drastically and resulting in the differential value of the un-pressed point not nearby point A, such as points B and B1 varying drastically as well, as shown in FIG. 2B.
The microprocessor (not shown) compares all the differential values with the threshold th0 so as to detect what point is pressed according to the comparing results. For example, the differential value of point A is the highest one and is over the threshold. Points A1 and A2 nearby point A are also over the threshold. The microprocessor determines that point A is pressed according to the differential values of points A1 and A2, wherein the judging method for determining what point is pressed is designed by the designer and installed in the microprocessor, as is known in the art.
With respect to points B and B1 not being nearby the pressed point A, the differential value of points B and B1 that are not pressed is also higher than the threshold th0, as shown in FIG. 2B. Thus, the microprocessor (not shown) regards point B as the pressed point according to comparing results and the same judging method. However, point B is not actually pressed, and thus point B is called a “Ghost Point,” as it is known in the art. This foregoing situation is called misreporting the touch point, represented by the word “misreporting”.
Thus, there is a need to provide a new touch-sensing display device to prevent misreporting of the touch point so as to further enhance touch efficiency.